Variable volume hydraulic motor with pressure responsive volume control



Feb. 2, 1954 E. F. MULLER VARIABLE VOLUME HYDRAULIC MOTOR WITH PRESSURE RESPONSIVE VOLUME CONTROL 2 Sheets-Sheet l Filed April '12, 1952 Feb- 2, 1954 E. F. MULLER Y,2,667,862 VARIABLE VOLUME HYDRAULIC MOTOR WITH PRESSURE RESPONSIVE VOLUME CONTROL 2 Sheets-Sheet 2 Filed April 11?I 1952 -lgn INVENTOR; ERNST F MULLER,

ATTY

Patented Feb. 2, 1954 UNITED STATES PATENT OFFICE VARIABLE VOLUME HYDRAULIC MOTOR' WITH PRESSURE RESPONSIVE VOLUME CONTROL of Ohio Application April 12, 1952, Serial No. 282,052

This invention relates to a variable volume type of hydraulic motor, and an object of the invention is to provide improved means for controlling automatically the volume of the motor for each revolution in response to the pressure of the hydraulic fluid delivered to said motor and in which means is provided to adjust the motor to maximum volume whenever the motor is iirst started in operation, after which the volume of said motor will be adjusted automatically as aforesaid.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings:

Fig. 1 is an elevational view, with parts broken away, showing an improved hydraulic motor incorporating features of my invention; and

Fig. 2 is a sectional view, with a part of the rotor and head shown in plan, of the motor oi Fig. 1. y

The hydraulic motor includes a main casting forming a housing or casing IIJ having a removable combination feed end cap and port plate II at one end and a bearing retaining cap I2 at the other end. Within the casing I there is a rotor I3 mounted on a drive shaft I4 which is carried in spaced anti-friction bearings I5 and I 6 carried adjacent opposite ends thereof.

The `rotor I3 is provided with a plurality of axially extending cylinders, one of which is seen at I1 in Fig. 2 of the drawings, within each of which cylinders there is a piston I8 having a bearing shoe I9 which rides on a thrust plate 20 carried by a trunnion 2i mounted for adjustment on an axis which is at right angles to the axis of the shaft I4 and includes a bearing shaft 22. Thrust received by the trunnion 2l is transmitted to the casing I0 through a pair of arcuate roller bearings 23,'the outer surface of the trunnion 2l being formed in an arc of a circle which rolls over said arcuate roller bearings 23.

The motor is preferably of a reversible character and is provided with feed and exhaust ports, one of which is seen at 24, there being a similar port diametrically opposed thereto in a manner well understood in this art. By making port 24 either a pressure port or an exhaust port; in other words, by connecting it selectively to the pressure line or the exhaust line, the direction of vrotation of the motor may be selectively controlled.

As best illustrated in Fig. 1 of the drawings ing the head of a push rod 25' which is' "urged 13 Claims. (Cl. 121-62) by a heavy spring 26 to the minimum volumetric position of the trunnion 2|, in which position the thrust plate 20 is in a plane substantially vertical with the axis of the shaft I4. 1t is obvious that when the thrust plate 29 is so positioned the pistons I3 will have little or no reciprocatory motion for each revolution of the rotor I3 and shaft I4. One end of the spring 2t abuts one end of a collar 2l carried by the push rod 25, the other end abutting an appropriate washer carried by the cap I I.

Diametrically opposite the push rod 25 there is a composite piston designated in its entirety by the reference character 28 which from a functional or operative standpoint includes two separate pistonsv 29 and 3i! formed integrally.

The piston 29 has a larger diameter than the piston 30, and the former reciprocates in a relattively large diameter cylinder 3l, the latter in a smaller diameter cylinder 32 which is formed by extending a sleeve 33 in one end of the cylinder 3! and adjacent the cap II, said sleeve 33.

being held in position by cooperating shoulders between it and the cylinder SI and by said cap Il, as is obvious from Fig. 1 of the drawings.

The principal portion of the piston 29 is pro-` vided with a relatively large bore 34 which receives an elongated pin `35 having a shoulder 3S formed thereon, which shoulder 36 cooperates with the bottom of the bore 34 to limit movement of the pin 35 toward the left as viewed in Fig. 1 of the drawings. the left by a helical spring which is held in adjusted position by a movable cap 3B threaded inthe bore 34, said cap 38 being provided with drain bores 39 to drain oil which may reach the bore 34. Thecap 38 is preferably hardened and cooperates with a hardened thrust button 40 carried by the trunnion 2 I.

It may be pointed, out at this time that hydraulic pressure on the piston 36 or on the piston 4 29, or both of them, will exert a force through said composite piston 28 tending .to rock the trunnion 2l in a direction against the action of the spring 26 and tending to increase the volume of the motorwhich, of course, means the volumetric consumptions for thereof. A

The left-hand portion of the pin 35 normally extends into a bore 4I which extends through the piston portion 3@ ofthe composite piston 28 and into a portion of the piston 29 thereof. The

composite piston 28 is provided with four radiali bores 42 spaced ninety degrees (90) apart, which under certain conditions provide a passageway- Said pin 35 is urged to each revolution for oil from the bore 4| to the large cylinder of the system asis the piston 30,Which, of course, 3|, to the end that said oil under pressure may is subject to said fluid pressure immediately upon operate on the piston 29 and urge said piston its being delivered to the cylinder 32. This force to the right to increase the capacity of the motor. developed by the pistons 29 and 30 is, of course,

As clearly illustrated in Fig. 1 of the drawings 5 transmitted through the head 28 to the button the pstonf29=has=a:portion adjacentritsfletfhand. 40- andaisnadequate toerockffthe -ftrunnion 2| end Whichis.reducedrrdiametnttliusrprovidflng; agaistr'ztkfeespring 25 ZVCto.theifmax'irnum voluin effect an operating chamber 43 to which hymetric position of the motor. In other Words, draulic fluid may be delivered under certain! 1 the thrust plate 20 will thus be moved to its conditions as hereinafter set forth to act on the 10 greatest angle so that the volume of the motor piston 29. A very small drairr'p'assageway54e wil-liib'ef a -maxirra-urn"v for each revolution, thus extends longitudinally alo11gf'the"cylinder`2!}"-toL providigamaxlnum torque and a minimum allow drainage of hydraulic fluid from the cham- Speed ofisai'd motor. This, of course, is the ber 43. This passageway Meisfsmallfenoughlthat desirablel starting@:characteristic of a hydraulic When fluid under pressurefsisidelivered.twthec'motorn chamber 43 it will not drain away fast enough AS the vehi'cle'ibeing moved gains in velocity to prevent operation of the pistorrl. the Ktendencyjvill.normally be for the required Hydraulic fluid delivered to"tlle" motor'under torque`to decrease and this would produce a pressure, either to the aforedescribed portllor; decreasefnthe pressure in the cylinder 32. This its companion port, not shown, is delivered to 20 decrease in pressure willallow the check valve thescylinder 432..byeitheroftvvo lnfanch,peassageaf-` 35i-ifiA to close, thus in eftect-shuttingoiihtheriow ways. Eil 'lolinsuretl'atlpassagewaysFV 45- will.'` 0f' hydralllllid t0@the-lge-:Cylndff 3L .Orts always connectitojhe ,pressure pol-17: rather than: n'Ol'herL'WOIdS, tothehambel. 43'. UnderjtheSe -th'exhaugtrport provide@ vtelIlk'noWn. fvrrm. 0f!k C0ndit01f1S-=the tllll'ln-n .postioningafole lisfdr autc'Jma-tic4 valve wvhichlincludesea pistonainraegs. veloped-\ entirely byj the piston-Jill, nor-1eroffo its cylinder 4 which is .connected =atopposite. ends-f bein'plodlid by Ythe-flllfgelff DlSfOrl.` 29e Pisten t@ ,passages/aye. 48" andgealone, QfE which iisazon-l 30 will` respond l automatically tot tha pressurel nectedto Y, one 0f tlfiecfportsw l sucho as` pori-o zf, delivered totthe cylinderg32rwhichlisthelpressure the-.other being-vconnectedltothe.other portlwhich. 0f-t1le.hyd1`all1f- Systemltol. adjust-the trunniom is vthe companinloilrsaidlport 2li;4 The pistonlAGLggl, 2l against the.: spring.,-.26i.so nlthat .the-Speedmi.U Willrespond automatically to connecapassagee. the mOtOI andY thus th Speed ofv thewdrivenl. Waysywwi'th., Whichever passageway ASQOLASS VehicleA WHbr$uC`haS-0mainlafilltheplessule undrlpressure. of' the hydraulic systenr.substantiallyaconstant@f THQ s operation .Y 0f the-. hydraulic.. motor. can.. Stated another Way,oncatheJiehiclerissiisnoppf prob'abIjr,best'beiundeistodlinmconnectign. Withfwelation the Smaller: kpiston.e3iwtafk1ese-COIllJrQIlfJLO a .typiczall operation -Wh'ereii such. a; motor... is` adjust. the-volumeofeoil.Vconsumedztbathemeter ernployem'v Such avimotoris useful,'.fr.example,-. per. revolution;.suchlthatetheespeed ofitheevehicllefg. as the driving,.,motor for thetraction Wheelsof Will consume the.- energy-,deliveredahydraalicalhei a. vehicle, for exampl,a shuttle.car,.loading,f by the-pump.. Theamotm'thereforefiseirneffect machine, orA mining machinellas usedllin Ycoal.,.4o.-anautomatic; speedregulator:becauseshould-:thee mines. Assumingrtlie vehicleltozb'elstandingrstilll Vehicle encounter significant resistance to speedi andtliesource offsupply, .suchasa pump, being.V it will .automaticallyeslew down Aini-:response:to in operation Vbut notconnectedltolthe motor. a rise in pressure;in;the:hydraulic:system:ll Garraf the control" valve. Assuming. further t.`ri'at '.tl:e. versely, when the.v vehicle 1 is.traveling^;; again '-g operator Wishes to starttlfieeveh'icleiand'operatesa f,e.lightresistance-:its fspeedeWi-ll lautomaticallw'fin; the control Valveto deliver hydrauliclii-idfundr ""'crease by#responding-2y to.-ther:hydrauliepressuree Dressur@ t0 @ne 0f 0h62 DQIS, SUCH as pmt. M-0f.- in' a-;manner toedecrease theecorrsumption ofioiljf.- said, motor. Sincer tli'ewel-iicleis4 atfrest iti is'` for: eac-hiflrevol-utionVoiitlreamotoraLA desirable that. it deliver maximum torque vatl It is particularly importantithatiuduring startfffr minimum speed to start itliin motion,- Tfiisvis Y i ing there are twopistoiesecoopeartingeto:oppose eected automatically in, 'the iollwingnmanner thfespririgi Maand,r,thussirisurefmaximumetorzueefbythe h'ydraulic'z.motorioffmy invention. 'lle-` withfafmi-rrimum .speedsfenamme-vga11mggwn hydraulic fluid d'lVeed CY1IdI1- sumptonofpthefmgtor; After this -bstarjjmg ffW through the passageway'Nandagainstthe masdmumltorquefandfmmimumispeemie issie end'of: theV pin 3,51 which' isl tvithinltli bllfe 4Vl i Dcrtantzthat the trunnion bie adjusted byiasingle?A apn'd- Win sul?? 02551.19' rfdla1-0fe$42- ThSWill 'j' piston:oriarpistonWhich'developsalessrtotal:thrust'e lsstsellll'stalrwlalljliirflIraglngsfrescre tha-nanasinvoiveddaringitheistarmnganerieae I the bol-s M andztvpvela'jersnslaee; LCbvionsl-ys.those fskfilledsimtherartsmy nietige@-v valvle which is. contained Within' tlie compositeY vaincusKh'ngesfwmmtheqetasanmamargemen i Y *y l Y i 6GlOfpartsawithout:departmgeiromsthe,splrrtnandr' piston 28,` v This pressure relief valve may,forscope oflltheinventiorrasiideneihyrfthef eXarnDlefl`besettoopen aUI'TO'Upfsif; vvheretllJ hereto appended", Yand:applicant' triereiore'e opgmtpgffessureof'theysifnf aPIQXmEP not', toA be:v restricted to the?precise'r construction 150 0l p..s. 1. and the overload .relief valve' ofthe herein disclosedf, @hilfe System 1S Set at 2000 P S 1- These DfeS- 651, raw-ingr'muydescribedlane:samen:zazmmscdiav sugs menixofxtheainvenuon,.wartime especificarse l. r fr presvsmefs cureibyr-Lettersfratenn.ofitneuriiteafststesas:v rst delivered to the cylinder 32 as aforesaid l. A-hydau-,motormcmdingpmeams fmedgf the pressurefwillbuildfupalmost instantaneously s m v f i f l tol-an. amount. adequatefto.y crackgthe Vrelief l valve. .7a provided-- by h'epn- 35;"Sp1ing .ShbOIfGS-M and! ingz'saidiadjustingfmeains:byl-hydraulicrnidurrderi 42, thuS'P-elml'tlng 'the hydraulicmfluid to flow pressure operating said motor, said hydraulica'l-ly:4A throughsa-id.; bore. 4L andithrougtn,thee-aradial,A operated mechanism includri'g-,imeansforminga bores-Metathe chamber 43, .,vvliereupon.theL-tlarg,e1Y pair. of; cylinders, piston: inl-.eachiofsada cyl# pistonlsavll'be subject tothahydraulictpressure..f.zagiinderssfor adjusting saiddjusting meansegoorrs `duit means for conducting Ysaid hydraulic iiuid to said cylinders, and valve means normally isolating one of said cylinders adapted to open and close at a predetermined hydraulic pressure whereby when the pressure of said nuid exceeds said predetermined pressure the uid may flow to said one cylinder.

2. A hydraulic motor including means `ior adjusting its hydraulic capacity for each revolution,

hydraulically operated mechanism for adjusting said adjusting means by hydraulic fluid under pressure operating said motor, said hydraulically operated mechanism including means forming a pair of cylinders of different internal diameters, a piston in each of said cylinders for adjusting said adjusting means, conduit means `for conducting said hydraulic fluid to the smaller pair of cylinders, a piston in each of said cylinders for adjusting said adjusting means, conduit means for conducting said hydraulic fluid to o ne of said cylinders, means forming a fluid passagewayy adapted to interconnect said cylinders, and means forming a valve responsive to i pressure in said one cylinder normally blocking said passageway and adapted to open and kclose yat a predetermined hydraulic pressure whereby when the pressure of fluid in said one cylinder exceeds said predetermined pressure it may now to and from the other cylinder.

4. A hydraulic motor including means for adjusting its hydraulic capacity for each revolution, hydraulically operated mechanism for adjusting said adjusting means by hydraulic uid under pressure operating said motor, said hydraulically operated mechanism including means forming a pair of cylinders, a piston in each of said cylinders for adjusting said adjusting means, one of said pistons including means forming a fluid passageway adapted to connect said cylinders, conduit means for conducting said hydraulic fluid to the cylinder having said passageway forming piston, and valve mea-ns associated with said passageway normally blocking it and adapted to open at a predetermined hydraulic pressure whereby when the pressure of said hydraulic fluid in said one cylinder is above said predetermined pressure said uid may low to said other cylinder.

5. A hydraulic motor including means for adjusting its hydraulic capacity for each revolution, hydraulically operated mechanism for adjusting said adjusting means by hydraulic iiuid under pressure operating said motor, said hydraulically operated mechanism including means forming a pair of axially aligned cylinders of diierent internal diameters, means forming interconnected pistons one in each of said cylinders including a passageway connecting said cylinders, conduit means for conducting said hydraulic uid to one of said cylinders, and valve means normally blocking said passageway adapted to open at a predetermined hydraulic pressure whereby when the pressure of said hydraulic ud in said one 6 cylinder exceeds said predetermined pressure iiuid may flow to both of said cylinders.

6. A hydraulic motor including means for adjusting its hydraulic capacity for each revolution, hydraulically operated mechanism for adjusting said adjusting means by hydraulic iluid under pressure operating said motor, said hydraulically operated mechanism including means forming a pair of axially aligned cylinders of different internal diameters, means forming interconnected pistons one in each of said cylinders, the smaller piston of which includes means forming a passageway interconnecting said cylinders, con-duit means for conducting said hydraulic fluid to the smaller of said cylinders, and a spring loaded valve means normally blocking said passageway adapted to open at a predetermined hydraulic pressure whereby when the pressure of said hydraulic iiuid in the smaller of said lcylinders exceeds said predetermined pressure hydraulic fluid may ow to said larger cylinder through said passageway.

7. A hydraulic motor including means `for adjusting its hydraulic capacity for each revolution, hydraulically operated mechanism for adjusting said adjusting means by hydraulic fluid under pressure operating said motor, said hydraulically operated mechanism including means forming a pair of axially aligned cylinders of diierent internal diameters, means forming interconnected pistons one in each of said cylinders, the smaller piston of which includes means forming a passageway interconnecting said cylinders, conduit means for conducting said hydraulic fluid to the smaller of said cylinders, and a spring loaded valve means normally blocking said passageway adapted to open at a predetermined hydraulic pressure whereby when the pressure of said hydraulic iluid in the smaller of said cylinders exceeds said predetermined pressure hydraulic fluid may flow to said larger cylinder through said passageway, said spring Iloaded valve means including a valve plunger and a spring carried Within the larger of said pistons.

8. A variable volume rotary hydraulic motor including a casing, a rotor mounted in said casing and having reciprocable cylinders, pistons in said cylinders, a thrust plate positioned to take the thrust of said pistons, means mounting said thrust plate for adjustment to adjust the volumetric consumption of said motor for each revolution, spring means urging said thrust plate toward a minimum consumption position, pressure responsive means opposing said spring means and urging said thrust plate to a maximum consumption position, said pressure responsive means including a line pressure chamber, a cylinder having a relatively large area and a second cylinder having a relatively small area, a. piston in each of said cylinders operative in response to pressure therein to urge said thrust plate in opposition to said spring means, means connecting said cylinder of relatively small area permanently to said line pressure chamber, and pressure responsive valve means for connecting said cylinder of relatively large area to said line pressure chamber whenever the line pressure reaches a predetermined value.

9. A variable volume rotary hydraulic motor including a casing, a rotor mounted in said casing and having reciprocable cylinders, pistons in said cylinders, a thrust plate positioned to take the thrust of said pistons, means mounting said thrust plate for adjustment to adjust the volumetric ein s aid ,motor for eaeh 'smieresponsive means; opposing' lsaid spr-ing meansiandzurgingf-said thrust plateto, amaximum consumption positions saidf presslirerespensive Ameans .inclu-ding a. line pressure; -chamber a pairof cylinders, a piston 'in eachfef -saidccylinders, operativefin response-to 'pressuretherei-ri to 4urge saidthrust-plate in opposition to said spring `Ineens;v means veenneoti ne one 4of said. pair .of Vazlzlinders permanently tesaid :line vpressure ,Qhambelhl and pressure: responsive. valve means for connecting the otherV of; said `pair of, cylinders toe said line? pressurechamber wheneverv the line pressinzeA reaches a predetermined-value;

1; Q. A pressure responsive `wvariable volume motorinchiding-amember' adjpstable; tovaryi the efectiva volume of' said 1119315012k el'vach -Izexzoluf tionimeans-urging said member` izo-a minimum uidapressurereaches iai predetermined valueeand cutting it oof; Qommun-cation- .therewith lwhen fluideV pressure drops; below said' predeterk lvalue.

111..,A. pressure ,nespensiyevariable volume motori incivil-Illiav z memiaerfadiustable; to vary the e.ifestive: volumevofrsaidmotor for each revolutien. means-urging; said,rrierpber:A tl a' minimum Volume; posit-ion; zuitpizessure responsive means .ui-gingsaid memberft maximum-mamme; .positi0p\,;saidaiuiximesponsiyefmeans :including-'a pair "'ofmistons-fone of whiohiisnomally monumentcation with: the fluid pressure-fair-14:1!pressureV Ite- V sponsive. valve mea-ns .fOr-puttingtheothery ofisaid pistons; in eommunfieationfwith-the luidpressure Wheneverv the fluid rpressurei-eaehes a-jprede- -termined valueandsouttingg it o-ff vof oommunica.-

-nected pistons, vonev iny .each yof :said lcplineleizs.;ra

passageway formedin the smalleresaid pistons connecting the twoe-oylinders-together said passageway is opere;andv axhigh pressure refsponsive valve includinga springhoused? the larger of saids-pistonsnormally closing set-impassageway; Y

13, A variable Volume hydraulic motorrinolufingf an adjustable velumemontlol membenpres.-

sure responsive;;means for; adiustingf'sa/idel volume control member inelxmliifigaY pai-r oifafli-gned eylinders of different diameters;` telifferentsize oonnected pistons, one each -of-saidfcylindersfa passageway formed in thesmaller vof said pistons connecting the two. cylinders together.- when, said passageway is open, rand' ay vhigh pressure.` responsive valve normally --closngfsaid passageway.

References Cited .in thefle-ofthis'ipatent UNITED STATESV PATENTS 

